Building Realistic Mobility Models for Mobile Ad Hoc Networks

A mobile ad hoc network (MANET) is a self-configuring wireless network in which each node could act as a router, as well as a data source or sink. Its application areas include battlefields and vehicular and disaster areas. Many techniques applied to infrastructure-based networks are less effective in MANETs, with routing being a particular challenge. This paper presents a rigorous study into simulation techniques for evaluating routing solutions for MANETs with the aim of producing more realistic simulation models and thereby, more accurate protocol evaluations. MANET simulations require models that reflect the world in which the MANET is to operate. Much of the published research uses movement models, such as the random waypoint (RWP) model, with arbitrary world sizes and node counts. This paper presents a technique for developing more realistic simulation models to test and evaluate MANET protocols. The technique is animation, which is applied to a realistic scenario to produce a model that accurately reflects the size and shape of the world, node count, movement patterns, and time period over which the MANET may operate. The animation technique has been used to develop a battlefield model based on established military tactics. Trace data has been used to build a model of maritime movements in the Irish Sea. Similar world models have been built using the random waypoint movement model for comparison. All models have been built using the ns-2 simulator. These models have been used to compare the performance of three routing protocols: dynamic source routing (DSR), destination-sequenced distance-vector routing (DSDV), and ad hoc n-demand distance vector routing (AODV). The findings reveal that protocol performance is dependent on the model used. In particular, it is shown that RWP models do not reflect the performance of these protocols under realistic circumstances, and protocol selection is subject to the scenario to which it is applied. To conclude, it is possible to develop a range of techniques for modelling scenarios applicable to MANETs, and these simulation models could be utilised for the evaluation of routing protocols

Building the Future Internet through FIRE

The Internet as we know it today is the result of a continuous activity for improving network communications, end user services, computational processes and also information technology infrastructures. The Internet has become a critical infrastructure for the human-being by offering complex networking services and end-user applications that all together have transformed all aspects, mainly economical, of our lives. Recently, with the advent of new paradigms and the progress in wireless technology, sensor networks and information systems and also the inexorable shift towards everything connected paradigm, first as known as the Internet of Things and lately envisioning into the Internet of Everything, a data-driven society has been created. In a data-driven society, productivity, knowledge, and experience are dependent on increasingly open, dynamic, interdependent and complex Internet services. The challenge for the Internet of the Future design is to build robust enabling technologies, implement and deploy adaptive systems, to create business opportunities considering increasing uncertainties and emergent systemic behaviors where humans and machines seamlessly cooperate

Revising the User Interface of NEMAN

This thesis is the final part of my Master Degree at the University of Oslo Department of Informatics. The thesis has been carried out under the supervision of Professor Thomas Plagemann and Phd. student Matija Pužar (Author of NEMAN) for the Distributed Multimedia Systems (DMMS) research group, the thesis itself is part of the Ad-hoc Infoware project. In this thesis we revise the graphical user interface (GUI) of the network emulator NEMAN. We discover that this interface has both technical issues and might also introduce copyright violation. Based on these facts we have designed and developed, with the C++ programming language and the Qt framework, a GPL licensed enhanced user interface, which consists of both a graphical and a command line interface. We have performed several analyses on both the old GUI and the new interface in order to compare the performance

Survey of context provisioning middleware

In the scope of ubiquitous computing, one of the key issues is the awareness of context, which includes diverse aspects of the user's situation including his activities, physical surroundings, location, emotions and social relations, device and network characteristics and their interaction with each other. This contextual knowledge is typically acquired from physical, virtual or logical sensors. To overcome problems of heterogeneity and hide complexity, a significant number of middleware approaches have been proposed for systematic and coherent access to manifold context parameters. These frameworks deal particularly with context representation, context management and reasoning, i.e. deriving abstract knowledge from raw sensor data. This article surveys not only related work in these three categories but also the required evaluation principles. © 2009-2012 IEEE

Building the Future Internet through FIRE

The Internet as we know it today is the result of a continuous activity for improving network communications, end user services, computational processes and also information technology infrastructures. The Internet has become a critical infrastructure for the human-being by offering complex networking services and end-user applications that all together have transformed all aspects, mainly economical, of our lives. Recently, with the advent of new paradigms and the progress in wireless technology, sensor networks and information systems and also the inexorable shift towards everything connected paradigm, first as known as the Internet of Things and lately envisioning into the Internet of Everything, a data-driven society has been created. In a data-driven society, productivity, knowledge, and experience are dependent on increasingly open, dynamic, interdependent and complex Internet services. The challenge for the Internet of the Future design is to build robust enabling technologies, implement and deploy adaptive systems, to create business opportunities considering increasing uncertainties and emergent systemic behaviors where humans and machines seamlessly cooperate

Secure Communication in Disaster Scenarios

Während Naturkatastrophen oder terroristischer Anschläge ist die bestehende Kommunikationsinfrastruktur häufig überlastet oder fällt komplett aus. In diesen Situationen können mobile Geräte mithilfe von drahtloser ad-hoc- und unterbrechungstoleranter Vernetzung miteinander verbunden werden, um ein Notfall-Kommunikationssystem für Zivilisten und Rettungsdienste einzurichten. Falls verfügbar, kann eine Verbindung zu Cloud-Diensten im Internet eine wertvolle Hilfe im Krisen- und Katastrophenmanagement sein. Solche Kommunikationssysteme bergen jedoch ernsthafte Sicherheitsrisiken, da Angreifer versuchen könnten, vertrauliche Daten zu stehlen, gefälschte Benachrichtigungen von Notfalldiensten einzuspeisen oder Denial-of-Service (DoS) Angriffe durchzuführen. Diese Dissertation schlägt neue Ansätze zur Kommunikation in Notfallnetzen von mobilen Geräten vor, die von der Kommunikation zwischen Mobilfunkgeräten bis zu Cloud-Diensten auf Servern im Internet reichen. Durch die Nutzung dieser Ansätze werden die Sicherheit der Geräte-zu-Geräte-Kommunikation, die Sicherheit von Notfall-Apps auf mobilen Geräten und die Sicherheit von Server-Systemen für Cloud-Dienste verbessert

Network Simulation Cradle

This thesis proposes the use of real world network stacks instead of protocol abstractions in a network simulator, bringing the actual code used in computer systems inside the simulator and allowing for greater simulation accuracy. Specifically, a framework called the Network Simulation Cradle is created that supports the kernel source code from FreeBSD, OpenBSD and Linux to make the network stacks from these systems available to the popular network simulator ns-2. Simulating with these real world network stacks reveals situations where the result differs significantly from ns-2's TCP models. The simulated network stacks are able to be directly compared to the same operating system running on an actual machine, making validation simple. When measuring the packet traces produced on a test network and in simulation the results are nearly identical, a level of accuracy previously unavailable using traditional TCP simulation models. The results of simulations run comparing ns-2 TCP models and our framework are presented in this dissertation along with validation studies of our framework showing how closely simulation resembles real world computers. Using real world stacks to simulate TCP is a complementary approach to using the existing TCP models and provides an extra level of validation. This way of simulating TCP and other protocols provides the network researcher or engineer new possibilities. One example is using the framework as a protocol development environment, which allows user-level development of protocols with a standard set of reproducible tests, the ability to test scenarios which are costly or impossible to build physically, and being able to trace and debug the protocol code without affecting results

IoT and Smart Cities: Modelling and Experimentation

Internet of Things (IoT) is a recent paradigm that envisions a near future, in which the objects of everyday life will communicate with one another and with the users, becoming an integral part of the Internet. The application of the IoT paradigm to an urban context is of particular interest, as it responds to the need to adopt ICT solutions in the city management, thus realizing the Smart City concept. Creating IoT and Smart City platforms poses many issues and challenges. Building suitable solutions that guarantee an interoperability of platform nodes and easy access, requires appropriate tools and approaches that allow to timely understand the effectiveness of solutions. This thesis investigates the above mentioned issues through two methodological approaches: mathematical modelling and experimenta- tion. On one hand, a mathematical model for multi-hop networks based on semi- Markov chains is presented, allowing to properly capture the behaviour of each node in the network while accounting for the dependencies among all links. On the other hand, a methodology for spatial downscaling of testbeds is proposed, implemented, and then exploited for experimental performance evaluation of proprietary but also standardised protocol solutions, considering smart lighting and smart building scenarios. The proposed downscaling procedure allows to create an indoor well-accessible testbed, such that experimentation conditions and performance on this testbed closely match the typical operating conditions and performance where the final solutions are expected to be deployed

Control logic distribution trade-offs in software-defined wireless networks

The SDN (Software-Defined Networks) architecture separates the data and the control planes of the networks. It logically centralizes the control of a network in a central point that is an SDN controller, which acts as a brain of the network and is in charge of telling each network node how to forward incoming packets by installing the appropriate forwarding rules. One of the main advantages it brings is programmability through this single entity (the logical controller) with which network management applications must interact to apply their policies. Through agreed-upon APIs, the network managers can exploit the full potential of SDN. SDN generally assumes ideal control channels between the SDN controller and the network nodes, which may not be the case in challenging environments that are becoming more common due to dense deployment of small cells (SCs) with reduced coverage in 5G and beyond 5G deployments. In 5G and beyond 5G use cases, cost-effective wireless transport networks are required to connect the SCs. In this context, mmWave technology is a good player to connect the SCs as mmWave provides larger radio spectrum chunks that in turn provide larger bandwidth and higher data rate. To manage the dense deployment of SCs in the mobile networks, on the network management/control front, network programmability and virtualization are also an integral part of 5G and beyond 5G networks. In this regard, to provide end-to-end connectivity, management and orchestration of all the segments of the networks ranging from RAN (Radio Access Network), transport network to the core is vital. On the transport networks side (the main focus of the dissertation), SDN plays an important role as SDN enables programmability and virtualization in the network. Though SDN Provides huge flexibility in network management by splitting the control plane from the data plane, it has some limitations in wireless networks context as separation of the control plane from the data plane introduce the extra points of failure in the SDN paradigm (e.g., control communication channel failure, SDN controller failure). In the wide-area networks (WAN) scenarios where in-band channels (e.g., microwave or mmWave links) are responsible to carry control traffic between the forwarding nodes and the SDN controller, the assumption of the availability of a reliable network may not be possible as the performance of the wireless link changes with the environmental conditions, which leads to a high risk of experiencing channel impairments, which might cause centralized SDN operation failure by affecting communication between the transport component of SCs and the SDN controller. To overcome SDN from failure, the dissertation presents a hybrid SDN scheme that explores the benefits of centralized and distributed operations depending on control communication channel conditions. Our hybrid SDN approach combines both centralized and distributed modes in the same node to form a hybrid control plane architecture. We introduce a local agent in the node that is composed of a monitoring framework to detect reliability of the control communication channel and a decision module that conceive a novel control logic switching algorithm to make a decision whether to operate in a centralized or distributed mode. We evaluate the proposed solution under a variety of unreliable network conditions (e.g., link impairments, control packet loss) to investigate the operational performance of the hybrid SDN during high loss conditions. The experimental results show that the proposed hybrid SDN solution substantially improves the aggregated throughput, particularly when control channel packet loss ratios increase, which in turn keeps the network operational in hard conditions where the centralized SDN would result in a non-operational network.La arquitectura SDN (Software-Defined Networks) separa los planos de datos y control de las redes. Centraliza lógicamente el control de una red en un controlador SDN. Una de las principales ventajas que aporta es la programabilidad a través de esta única entidad (el controlador lógico) con la que las aplicaciones de gestión de red deben interactuar para aplicar sus políticas. SDN generalmente asume canales de control ideales entre el controlador SDN y los nodos de la red, lo que puede no ser el caso en entornos inalámbricos (o menos estables) que se están volviendo más comunes debido al despliegue denso de celdas pequeñas (SC) con cobertura reducida en 5G (y más allá). En los casos de uso de futuras redes, se requieren redes de transporte inalámbricas rentables para conectar los SC. En este contexto, la tecnología mmWave es apropiada para conectar las SC, ya que mmWave proporciona fragmentos de espectro más grandes que, a su vez, proporcionan un mayor ancho de banda y una mayor velocidad de datos. Para administrar el despliegue denso de SC en redes móviles, se requiere administración/control de la red, de la virtualización y de la programabilidad de la red, ay que son parte integral de las redes 5G/6G. En este sentido, para proporcionar conectividad de extremo a extremo, es vital la gestión y la orquestación de todos los segmentos de red que van desde la RAN (Red de acceso radio), la red de transporte hasta el núcleo de la red. Por lo que respecte a las redes de transporte (el enfoque principal de la tesis), SDN juega un papel importante ya que SDN permite la programabilidad y la virtualización en la red. Aunque SDN proporciona una gran flexibilidad en la gestión de redes al dividir el plano de control del plano de datos, tiene algunas limitaciones en el contexto de las redes inalámbricas, ya que la separación del plano de control del plano de datos introduce puntos adicionales de fallo en el paradigma SDN (p. ej., fallo del canal de comunicación, fallo del controlador SDN). En los escenarios de redes de área extendida (WAN) donde los canales en-banda (p. ej., enlaces de microondas o mmWave) son responsables de transportar el tráfico de control entre los nodos de red y el controlador SDN, la suposición de la disponibilidad de una red confiable puede no ser posible, ya que el rendimiento del enlace inalámbrico cambia con las condiciones ambientales, lo que conduce a un alto riesgo de experimentar deterioros en el canal, lo que podría causar errores en la operación SDN centralizada al afectar la comunicación entre el componente de transporte de los SC y el controlador SDN. Para superar estos problemas de SDN, la tesis presenta un esquema de SDN híbrido que explora los beneficios de las operaciones centralizadas y distribuidas según sean las condiciones del canal de comunicación de control. Nuestro enfoque SDN híbrido combina los modos centralizados y distribuidos en el mismo nodo para formar una arquitectura de plano de control híbrido. Introducimos un agente local en el nodo que se compone de un marco de monitorización para detectar la confiabilidad del canal de comunicación de control y un módulo de decisión que concibe un algoritmo de conmutación de lógica de control novedoso para tomar la decisión de operar en un modo centralizado o distribuido. Evaluamos la solución propuesta bajo una variedad de condiciones de red poco confiables (p. ej., deterioros de enlace, pérdida de paquetes de control) para investigar el rendimiento operativo de la SDN híbrida durante condiciones de alta pérdida. Los resultados experimentales muestran que la solución SDN híbrida propuesta mejora sustancialmente el rendimiento agregado, particularmente cuando aumentan las tasas de pérdida de paquetes del canal de control, lo que a su vez mantiene la red operativa en condiciones difíciles donde la SDN centralizada daría como resultado una red no operativa.Postprint (published version